Features: 1. Turn any hollow core into a speaker: These bone conduction speakers are the smallest and most versatile bone conduction speakers available, allowing you to enjoy a unique sound experience in any environment. Transform any hollow surface into a speaker anytime, anywhere. 2. Different sounds with different surfaces: Using bone conduction technology, this speaker provides a customizable o experience. Enjoy varied sound outputs by placing it on different surfaces such as glasses, guitars, cardboard boxes, plastic containers, photo frames, headphones, or dashboards. Each surface delivers a distinct acoustic effect. 3. Portability: Compact and lightweight design makes this speaker easy to carry and use on the go. 4. Small but powerful: When paired with the right surface, the speaker delivers strong o output up to 115 decibels, with adjustable sound quality. Best performance is achieved with thin, resonant materials such as plastic containers or buckets. 5. Multifunctional use: Use the bone conduction speaker for listening to music, podcasts, making hands-free phone calls, participating in conference calls, playing games, or enhancing gaming o. The built-in FM radio allows you to tune in to music and podcasts. Specifications: Capacity: 400mAh Functions: Bone Conduction Speaker, FM Radio Wireless Version: 5.0, A2DP, HFP Wireless Stereo Supported: Yes Built-in FM Radio: Yes Bone Conduction Transducer: 3Watt Frequency Range: 120Hz - 16kHz Built-in High-Sensitivity Microphone: Yes Battery: 400mAh Polymer Battery Charging Port: USB-C (not compatible with fast charging) Note: For optimal FM performance, use outdoors and connect the USB cable during use. Material: Metal Color: Black Package Contents: 1 x Bone Conduction Speaker 1 x Charging Cable Note: The product image may differ slightly in color due to lighting and screen settings. Measurement may vary by +/- 1-3cm.